Extrusion systems are well known in the art for extruding strips of polymeric material onto a surface of a roller. The extruded component is temporarily carried by the roller and then travels downstream of the roller where it may be further processed into specific rubber tire tread lengths by way of example. Typical extrusion systems include an extruder head which conveys a flow of material through a laterally expanding flow channel to a discharge outlet of the head. Oftentimes, it is necessary to shape the extruded material from the extruder head into a more specific shape before it is extruded through a final profile die onto the surface of the roller.
To this end, roller die preformers are used to shape the flow of material in the interim area between the discharge outlet of the extruder head and the outer circumferential surface of the roller. The preformer is connected in fluid communication with the discharge outlet of the extruder head and is further positioned very close to or even in contact with the roller. The preformer includes a flow inlet configured to receive a flow of material from the discharge outlet of the extruder head and a flow outlet configured to form the extruded component on the surface of the roller.
In the past, roller die preformers have been configured with a flow inlet having a lateral width which is generally equal to the lateral width of the discharge outlet of the extruder head, and further with a flow outlet having a lateral width which is generally narrower than or as wide as the lateral width of the flow inlet. A flow channel is provided within the preformer to convey the flow of material between the flow inlet and the flow outlet so that the extruded component on the surface of the roller may have a lateral width which is narrower than or as wide as the lateral width of the flow inlet depending on the configuration of the preformer. A profile die is mounted to the preformer to profile the extruded material as it exits the flow outlet and is thereafter extruded onto the surface of the roller.
A problem occurs when it is desirable to form an extruded component having a lateral width which is wider than the lateral width of the discharge outlet of the extruder head. In the past, this has required a change to a larger extruder head having an appropriately sized discharge outlet for the desired lateral width of the extruded component. For example, if a thirty-four (34) inch wide extruded component is desired, an extruder head having a discharge outlet with the same or even a wider lateral width has been required. Of course, it will be appreciated that such a change results in a significant expense for the purchase of a wider extrusion head, significant labor and lost production costs associated with installing the wider extruder head, and lost production time as current dies must be redeveloped for the wider extruder head.
Therefore, there is a need for an extrusion system which is capable of forming a variety of extruded component widths on the surface of a roller during an extrusion process while overcoming the drawbacks and shortcomings of extrusion systems heretofore known.